Magnetic thin film, magnetic component that uses this magnetic thin film, manufacturing methods for the same, and a power conversion device

ABSTRACT

On top of a silicon substrate, a polyimide film with a thickness of 10 μm is formed. On top of this, a magnetic thin film that is a polyimide film containing Fe fine particles and that has a thickness of 20 μm is formed. On top of this magnetic thin film, a patterned Ti/Au film and a Ti/Au connection conductor are formed. On top of this, a polyimide film with a thickness of 10 μm, and a Cu coil with a height 35 μm, width 90 μm, space 25 μm, and a polyimide layer that fills the spaces in the Cu coil are formed. On top of this, via a polyimide film with a thickness of 10 μm, a magnetic thin film that is a polyimide film containing Fe particles and that has a thickness of 20 μm is formed. This thin film inductor has a small alternating current resistance. The present invention provides a magnetic thin film that is well suited for mass production, can be manufactured easily, can be made into a thick film, has soft magnetic qualities, and is inexpensive. The present invention also provides a magnetic component that uses this magnetic thin film, manufacturing methods for these, and a power conversion device.

BACKGROUND OF THE INVENTION

The present invention relates to a magnetic thin film that can act as amagnetic core for a magnetic component such as a reactor, transformer,and magnetic head and the like. The present invention also relates to amagnetic component in which this magnetic thin film is formed on top ofa semiconductor substrate. The present invention also relates to theirmanufacturing methods. The present invention also relates to a powerconversion device.

In the prior art, the magnetic thin film that is the magnetic core ofmagnetic components such as reactors, transformers, and magnetic heads,and the like is generally manufactured by methods such as sintering,rolling, plating, and sputtering of magnetic materials.

Depending on the usage of the magnetic component, different magneticqualities are needed. As a general classification, there are hardmagnetic qualities and soft magnetic qualities. In hard magneticqualities, the B-H quality has an angular hysterisis and has a highcoercive force. A magnetic component having these hard magneticqualities include magnetic recording medium and the like. For softmagnetic qualities, the B-H quality has a small coercive force. Magneticcomponents having this soft magnetic quality include power sourcecomponents such as inductors and transformers which need to have lowmagnetic loss. For the magnetic qualities of these magnetic componentsused in power source components, they must have a high magneticpermeability and must have low overcurrent loss caused by the magneticlines of force inside the magnetic body. As a result, for the magneticmaterials that form the magnetic components used in power sourcecomponents, magnetic qualities of a high magnetic permeability as wellas a high electric resistance are desired.

For the magnetic qualities of magnetic components used in power sourcecomponents, a coercive force (Hc) of 40 mA/m or less, a saturationmagnetic-flux density (Bs) of 1 T or greater, a magnetic permeability(mu) on the order of several thousand (MHz), and an electricalresistance (rho) of 10⁻⁶/ohm m or greater have been sought. Magneticcomponents formed from Co type amorphous magnetic thin films formed bysputtering and the like have been implemented.

Referring to FIG. 14, there is shown a structural diagram of a thin filminductor formed on top of a silicon substrate by a sputtering method.Referring to FIG. 14(a), there is a plan view, and referring to FIG.14(b), there is a cross-section cut along line A-A of FIG. 14(a). Thisthin film inductor has a thickness of 60 micrometers. It is constructedby sandwiching a planar spiral coil of copper (a Cu coil 104) between amagnetic thin film 103 and a magnetic thin film 106. Magnetic thin film103 and magnetic thin film 106 are Co amorphous and are formed bysputtering. Referring to the figure, a two-turn coil is shown, but inpractice, coils of several turns to several tens of turns are used.Furthermore, referring to the figure, there are a silicon substrate 101on which an IC or switching element is formed, a polyimide film 102,magnetic thin film 103 of CoHfTaPd, a polyimide film 105, magnetic thinfilm 106 of CoHfTaPd. A connection conductor 107 connects an end part ofthe central part of Cu coil 104 with the switching element formed onsilicon substrate 101. Connection conductor 107 is formed at the sametime as when Cu coil 104 is formed.

Referring to FIG. 15, the process for manufacturing the magnetic thinfilm that is formed by the sputter method is shown. Referring to FIGS.15(a) to 15(d), there are shown cross sections of the manufacturingprocess in the process sequence. This is the process for manufacturingthe thin film inductor of FIG. 11.

A silicon substrate 81 has a built-in semiconductor element, such as ICor a switching element. After coating and baking a non-photosensitivepolyimide 82 (thickness 5 μm) onto silicon substrate 81, a CoHfTaPd film83 (thickness 9 μm) is formed by a sputter method (FIG. 15(a)). Next, anon-photosensitive polyimide 84 (thickness 5 μm) is again coated andbaked. Ti/Au (=0.5/0.1 μm) is formed by a sputter method, and patterningis conducted, and this becomes a plated electrode layer 85 (FIG. 15(b)).At this time, in order to have an electrical connection with theswitching element formed on silicon substrate 81, a connection conductor90 is formed at the same time as the formation of plated electrode layer85. Next, a photosensitive polyimide film 86 is coated and baked, andpatterning is conducted, and a plating mask (thickness 30 micrometers)is formed, and a Cu coil 87 is formed by plating (FIG. 15(c)).Afterwards, a non-photosensitive polyimide 88 (thickness 5 micrometers)is coated and baked. A magnetic thin film 89 of CoHfTaPd film (thickness9 micrometers) is formed by sputter method, and the inductor iscompleted (FIG. 15(d)). Referring to Table 1, the qualities of aninductor created in this manner is shown. TABLE 1 Qualities of a thinfilm inductor of the prior art (4 mm square, 16 turns) Frequency 3 MHz,Operating conditions driving current 0.35 A Inductance value L (μH) 0.95Direct current resistance Rdc (ohm) 0.8 Alternating current resistanceRac (ohm) 5.38

In this table, the larger the inductance value L and the smaller thedirect current resistance Rdc and the alternating current resistanceRac, the better the quality of the inductor.

For the manufacturing method for the magnetic thin film, when theaforementioned sintering or rolling is used, high temperature treatmentof around 1000° C. is required. As a result, it is difficult to form amagnetic thin film on top of a semiconductor substrate which has abuilt-in IC (integrated circuit) and the like. Furthermore, when usingplating, although manufacture by normal temperature treatment ispossible, the control of the film thickness of the magnetic thin film isdifficult. As a result, it is difficult to obtain a good magneticquality. Furthermore, with the sputter method as described above, thisis the method that is most generally used. However, the manufactureprocess is complex, and mass production is difficult. Therefore, themanufacture cost of magnetic components using this magnetic thin film ishigh. Furthermore, because the speed of growth is slow with the sputtermethod, making a thick film is difficult.

Stated more concretely, when forming a Co type amorphous magnetic thinfilm by sputtering, the speed of accumulation is slow (˜2 μm/h). Whenmass production is considered, 9 μm is the limit for its film thickness.Currently, the magnetic thick film is implemented at this thickness.Even if mass production is not considered, if the thickness is made anygreater, there can be cracking and loss due to membrane stress.

In one example of the prior art-for the formation of the magnetic filmby sputter method, a magnetic metal (Fe, Co, FePt, and the like) and anoxide with a large oxide heat of formation (Al₂O₃ and the like) aresimultaneously sputter deposited. The magnetic thin film has a structurecomprising particle masses of magnetic metal granules and insulatingnon-metals that surround these granules (H. Fujimori: Scriptametallurgica et materialia, 33, 1625 (1995), S. Ohnuma, et al: J. Appl.Phys. 79, 5130 (1996), S. Kobayashi et al: Nihon OuyouJ Jiki Gakkai-shi20,469 (1996), S. Ohnumaet al: J. Appl. Phys., 85,4574 (1999), and thelike).

This magnetic thin film is called a metal-non-metal granular film.Compared to-the usual magnetic thin film, it has a large electricalresistance. In addition, it is know to show excellent soft magneticqualities in the high frequency region. Here, metal-non-metal granularfilms refer to films in which magnetic metal granules are dispersed in aresin and the like. The magnetic metal granules are metal particles(magnetic particles of Fe and the like) covered by a non-metal film (aninsulating film such as oxide film and the like). Metal-non-metalgranular films can also refer to films in which these magnetic metalgranules are aggregated.

However, with magnetic thin films formed in this manner, because asputter method is used, the manufacturing costs are high, and making athick film is difficult.

Furthermore, in general in the prior art, a magnetic core of atransformer is manufactured by sintering, rolling, plating, sputtering,and the like of magnetic materials. With sintering or rolling, with hightemperature treatment of around 1000° C., a bulky magnetic core isformed. This type is the standard. Transformers are necessary as aninsulated switching power source component. In recent years, there hasbeen demand for smaller, thinner, and lighter components. In respondingto this demand, this bulky transformer of the prior art has been a largebottleneck. Recently, instead of these bulky transformers, thin filmtransformers in which a thin film coil is sandwiched between magneticthin films have been proposed. Referring to FIG. 16, there is a planview (FIG. 16(a)) of a thin film transformer of thickness 100 μm that iscreated on top of a silicon substrate. Referring to FIG. 16 b, there isa cross-section along section A-A′. A primary and a secondary planarspiral coil of copper (thickness 30 μm, width 90 μm, spacing 5 μm) aresandwiched by Co amorphous magnetic thin films (thickness 9 μm) that areformed by a sputter method (in the figure, for simplicity, a two turncoil is shown, but in reality, a sixteen turn coil is used). Referringto FIG. 17, a flow diagram of the prior art is shown. A siliconsubstrate 171 has a built-in semiconductor element. After coating andbaking a non-photosensitive polyimide 172 (thickness 5 μm) onto siliconsubstrate 171, a CoHfTaPd film 173 (thickness 9 μm is formed by sputtermethod (FIG. 17(a)). Next, a non-photosensitive polyimide 174 (thickness5 μm) is coated and baked again, and a Ti/Au film 175 (=0.5/0.1 μm) isformed by sputter method. Patterning is conducted and a plating mask(photosensitive polyimide) 176 (thickness 30 μm) is formed. Cu platingis conducted, and a primary coil 177 is formed (FIG. 17(c)). Afterwards,the process in FIG. 17(b) is repeated, and a non-photosensitivepolyimide 178 (thickness 5 μm), a plated electrode layer 179 of Ti/Au(=0.5/0.1 m) are formed (FIG. 17 d). Furthermore, the process in FIG. 17c is repeated. After coating and baking a plating mask (photosensitivepolyimide) 180 (thickness 5 μm), non-photosensitive polyimide film 182is formed. Similarly, a secondary coil 181 is provided, and a CoHfTaPdfilm 183 (thickness 9 μm) is formed by sputter method, and thetransformer is completed (FIG. 17(e)). The electrical connection partwith the coil is omitted, but a contact part is formed. For convenience,the primary and the secondary coils are shown having equal turn numbers,however, if the input output voltage ratio is changed, they can beformed in the same manner with different turn numbers. With thisstructure of the prior art, the distance between magnetic thin filmsbecome large (in the figure, it is 75 μm), and the leakage flux becomeslarge. The interlinkage flux between the primary and secondary coils isreduced, and as a result, the magnetic bond between them is weakened,and the output from the primary side is not efficiently transmitted tothe secondary side. As a result, with the construction of the prior art,in general, the transformer has a low conversion efficiency.

Furthermore, in the prior art, for the lead wires, enamel wires that arecovered with enamel are known. With this type of covered wire, in orderto maintain electrical insulation even if there is contact betweenconductors, the wires are covered with an insulating material. However,in recent years, in conjunction with the miniaturization and highdensity mounting of electrical components, there have been problems withelectromagnetic interference. Because the coated wires of the prior areonly for electrical insulation, the mutual interference from themagnetic fields created by current flowing in the lead wires cannot beavoided. Therefore, if the lead wires are covered with a film that canact as an electromagnetic shield, this problem can be avoided.

Furthermore, a power conversion device such as a DC-DC converter and thelike has a power source module. In this power source module, individualcomponents of switching element, rectifying element, condenser, controlIC and magnetic induction components of coil and transformer and thelike are formed as a hybrid on top of a printed substrate of ceramic orplastic and the like. The miniaturization of hybrid power source moduleshas advanced due to technology such as MCM (multi-chip module), and thelike. However, the miniaturization of magnetic induction components suchas coil and transformer and the like is difficult. Because these take upa large volume, the miniaturization of the power source module islimited. In recent years, with the use of semiconductor technology,there have been reports of examples of thin micro-magnetic elements(coil, transformer) mounted on top of a semiconductor substrate. Forexample, in Japanese Laid-Open Patent Application Number 8-149626, aplanar magnetic inductor component is disclosed. However, using thinfilm technology, the process for forming a planar magnetic inductioncomponent on top of a substrate with a built-in semiconductor integratedcircuit is complex and lengthy. Furthermore, when the planar magneticinduction component is formed by a thin film process, the magnetic thinfilm and the insulating filler material shrink due to heat treatment.With this stress, there can be warping of the substrate, and processingbecomes difficult.

The above, and other objects, features and advantages of the presentinvention will become apparent from the following description read inconjunction with the accompanying drawings, in which like referencenumerals designate the same elements.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the present invention is to provide a magnetic thinfilm that is well suited for mass production, can be manufacturedeasily, can be made into a thick film, has soft magnetic qualities, andis inexpensive. The present invention also provides a magnetic componentthat uses this magnetic thin film, manufacturing methods for these, anda power conversion device.

In order to achieve the above objective, the following are implemented.

-   1) A magnetic thin film, comprising:    -   a resin in which magnetic fine particles are dispersed.-   2) A magnetic thin film as described in Item 1), wherein:    -   the magnetic fine particles contain at least one metal element        selected from a group consisting of Fe, Ni, Co, Mn, and Cr.-   3) A magnetic thin film as described in Item 1) or 2), wherein:    -   the resin is a non-photosensitive resin or a photosensitive        resin.-   4) A magnetic thin film as described in one of Items 1) through 3),    wherein:    -   the resin is an organic magnetic polymer.-   5) A magnetic thin film as described in Item 4), wherein:    -   the organic magnetic polymer is a cross conjugated polycarbene        or a conjugated polymer that has a main chain of polyacetylene        and polydiacetylene.-   6) A magnetic thin film, wherein:    -   the thin film is constructed from magnetic fine particles, and        the fine particles are aggregated so that the fine particles are        in contact with each other.-   7) A magnetic thin film as described in one of Items 1) through 6),    wherein:    -   the fine particle comprises a magnetic particle and an        insulating film that surrounds the perimeter of the magnetic        particle.-   8) A manufacturing method for a magnetic thin film, comprising:    -   a process for dispersing magnetic fine particles in a medium;    -   a process for coating the medium on top of an insulating film;    -   a process for heat treating and solidifying the medium.-   9) A manufacturing method for a magnetic thin film as described in    Item 8), wherein:    -   the medium is anon-photosensitive resin solution or a        photosensitive resin solution.-   10) A manufacturing method for a magnetic thin film, comprising:    -   a process for dispersing magnetic fine particles in a medium;    -   a process for coating the medium on top of an insulating film;    -   a process for heat treating, evaporating, and removing the        medium.-   11) A manufacturing method for a magnetic thin film as described in    Item 10), wherein:    -   the medium is toluene.-   12) A magnetic component, comprising:    -   a first magnetic thin film and a second magnetic thin film being        magnetic thin films described in one of Items 1) through 7);    -   the first magnetic thin film being formed on top of a        semiconductor substrate via an insulating film;    -   a thin film conductor being formed in a spiral shape on top of        the first magnetic thin film;    -   a second resin that fills spaces in the spiral thin film        conductor;    -   the second magnetic thin film being formed on top of the thin        film conductor and the second resin.-   13) A magnetic component as described in Item 12), wherein:    -   the second resin is a magnetic thin film as described in one of        Items 1) through 5).-   14) A magnetic component, comprising:    -   a third magnetic thin film and a fourth magnetic thin film being        magnetic thin films described in Item 6);    -   the third magnetic thin film being formed on top of a        semiconductor substrate via an insulating film;    -   a thin film conductor being formed in a spiral shape on top of        the third magnetic thin film;    -   the third magnetic thin film being formed in spaces in the        spiral thin film conductor;    -   the fourth magnetic thin film being formed on top of the thin        film conductor and the third magnetic thin film.-   15) A manufacturing method for a magnetic component, comprising:    -   a first magnetic thin film and a second magnetic thin film being        magnetic thin films described in one of Items 1) through 5);    -   a process for forming the first magnetic thin film on top of a        semiconductor substrate via an insulating film;    -   a process for forming a thin film conductor in a spiral shape on        top of the first magnetic thin film;    -   a process for filling a second resin in spaces in the spiral        thin film conductor;    -   a process for forming the second magnetic thin film on top of        the thin film conductor and the second resin.-   16) A manufacturing method for a magnetic component as described in    Item 15), wherein:    -   the second resin is a magnetic thin film described in one of        Items 1) through 5).-   17) A manufacturing method for a magnetic component, comprising:    -   a third magnetic thin film and a fourth magnetic thin film being        magnetic thin films described in Item 6);    -   a process for forming the third magnetic thin film on top of a        semiconductor substrate via an insulating film;    -   a process for forming a spiral-shaped thin film conductor on top        of the third magnetic thin film;    -   a process for forming the third magnetic thin film in spaces in        the spiral-shaped thin film conductor;    -   a process for forming the fourth magnetic thin film on top of        the thin film conductor and the third thin film.-   18) A magnetic component, comprising:    -   a first magnetic thin film and a second magnetic thin film being        magnetic thin films described in one of Items 1) through 5);    -   the first magnetic thin film being formed on top of an        insulating substrate via an insulating film;    -   a thin film conductor being formed in a spiral shape on top of        the first magnetic thin film;    -   a second resin filling spaces in the spiral-shaped thin film        conductor;    -   the second magnetic thin film being formed on top of the thin        film conductor and the second resin.-   19) A magnetic component as described in Item 18), wherein:    -   the second resin is a magnetic thin film as described in one of        Items 1) through 5).-   20) A magnetic component, comprising:    -   a third magnetic thin film and a fourth magnetic thin film being        magnetic thin films described in Item 6);    -   the third magnetic thin film being formed on top of an        insulating substrate via an insulating film;    -   a thin film conductor being formed in a spiral shape on top of        the third magnetic thin film;    -   the third magnetic thin film being formed in spaces in the        spiral-shaped thin film conductor;    -   the fourth magnetic thin film being formed on top of the thin        film conductor and the third magnetic thin film.-   21) A magnetic component as described in one of Items 12) through    14), wherein:    -   the magnetic component is a transformer.-   22) A magnetic component as described in one of Items 12) through    14), wherein:    -   the magnetic component is a power conversion device.-   23) A lead wire, wherein:    -   the lead wire is covered with a magnetic thin film described in        one of Items 1) through 7).-   24) A magnetic component, comprising:    -   a lead wire as described in Item 23) being used as a coil.-   25) A current sensor, comprising:    -   a magnetic sensor being provided on a lead wire described in        Item 23).-   26) A magnetic component as described in one of Items 12) through    14), comprising:    -   an insulating film being between the first magnetic thin film        and the thin film conductor and the second resin and between the        thin film conductor and the second resin and the second magnetic        thin film.-   27) A magnetic component as described in one of Items 12) through    14), wherein:    -   the thin film conductor and the second resin is formed as two        layers via an insulating film.-   28) A power conversion device, comprising:    -   a magnetic component, comprising:        -   a magnetic thin film as described in one of Items 1)            through 7) being formed on top of a semiconductor integrated            circuit substrate via an insulating film;        -   a thin film conductor being formed in a spiral shape on top            of the magnetic thin film;        -   a second resin being filled in spaces in the spiral-shaped            thin film conductor;    -   the magnetic component being mounted on top of a wiring        substrate;    -   the magnetic component being resin sealed by a resin in which        magnetic fine particles are dispersed.-   29) A power conversion device, comprising:    -   a magnetic component, comprising:        -   a magnetic thin film as described in one of Items 1)            through 7) being formed on top of a semiconductor integrated            circuit substrate via an insulating film;        -   a thin film conductor being formed in a spiral shape on top            of the magnetic film;        -   a second resin being filled in spaces in the spiral-shaped            thin film conductor;    -   the magnetic component being mounted onto a lead frame;    -   a lead terminal being connected to the magnetic component by a        metal thin wire;    -   the lead terminal and the lead frame and the magnetic component        are resin sealed by a resin in which magnetic fine particles are        dispersed.-   30) A power conversion device as described in Item 28) or 29),    wherein:    -   the thin film conductor and the second resin are formed in two        layers via an insulating film.-   31) A power conversion device as described in Item 28) or 29),    wherein:    -   an insulating film is formed on top of the thin film conductor        and the second resin.

As described above, fine particles of magnetic material are dispersed ina medium of resin or a solvent. This medium is coated, dried, andsintered. With this simple method, a magnetic thin film that is suitedfor mass production, is easy to manufacture, can be made into a thickfilm, and has soft magnetic qualities can be manufactured inexpensively.Furthermore, magnetic components using this magnetic thin film and powerconversion devices can also be manufactured inexpensively.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section of the principal parts of a magnetic thin filmof a first embodiment of the present invention.

FIG. 2 is a second embodiment of the present invention and is themanufacturing method for the first embodiment of the magnetic thin film.

FIG. 3 is a third embodiment of the present invention and is across-section of a thin film inductor using the magnetic thin film ofthe first embodiment.

FIG. 4 is a fourth embodiment of the present invention and shows amanufacturing method for the thin film inductor of the third embodiment.

FIGS. 4(a)-4(c) show cross-sectional diagrams of the manufacturingprocess in the process sequence.

FIG. 5 is a cross-section of the principal parts of a thin film inductorof a fifth embodiment of the present invention.

FIG. 6 is a sixth embodiment of the present invention and shows amanufacturing method for the thin film inductor of the fifth embodiment.

FIGS. 6(a)-6(c) show cross-sectional diagrams of the manufacturingprocess in the process sequence.

FIG. 7 is a cross-section of the principal parts of a thin film inductorof a seventh embodiment of the present invention.

FIG. 8 is an eighth embodiment of the present invention and shows amanufacturing method for the thin film inductor of the seventhembodiment.

FIGS. 8(a)-8(c) show cross-sectional diagrams of the manufacturingprocess in the process sequence.

FIG. 9 is a cross-section of the principal part of a thin film inductorof a ninth embodiment of the present invention.

FIG. 10 is a cross-section of the principal part of a thin film inductorof a tenth embodiment of the present invention.

FIG. 11 is a cross-section of the principal part of a thin film inductorof an eleventh embodiment of the present invention.

FIG. 12 is a first schematic drawing of the magnetic thin film of thepresent invention.

FIG. 13 is a second schematic drawing of the magnetic thin film of thepresent invention.

FIG. 14 is a structural drawing of a thin film inductor that is formedon top of a silicon substrate by the sputter method. FIG. 14(a) is aplan view, and FIG. 14(b) is a cross-section drawing cut along line A-Aof FIG. 14(a).

FIG. 15 is a manufacturing process for the magnetic thin film created bythe sputter method.

FIGS. 15(a) to 1 5(d) are cross-sections of the manufacturing process inthe process sequence.

FIG. 16(a) is a plan view of a thin film transformer with a thickness of100 μm created on top of a silicon substrate.

FIG. 16(b) is a cross-sectional drawing of section A-A′.

FIG. 17 is a manufacture process flow diagram for a transformer of theprior art.

FIG. 18 is a cross-section drawing of one example of a thin filmtransformer of a twelfth embodiment of the present invention.

FIG. 19 is a thirteenth embodiment of the present invention and shows amanufacture process flow diagram of the thin film transformer of FIG.18.

FIG. 20 is a cross-section of a lead wire which is a fourteenthembodiment of the present invention.

FIG. 21 is a figure for explaining the device for manufacturing the leadwire of the fourteenth embodiment of the present invention.

FIG. 22 is a sketch drawing of a coil in which the lead wiremanufactured in the fourteenth embodiment is wound into a spring shape.

FIG. 22(b) is a partial cross-section along surface A-A′.

FIG. 23 is a figure for describing the magnetic field generated by thecurrent flowing through the coil of FIG. 22.

FIG. 24 is a figure for describing the situation when coils are placedin close contact.

FIG. 25 is a figure for describing an example when the principles inFIG. 24 is applied to a current detection sensor.

FIG. 26 is a cross-section of a power conversion device of a fifteenthembodiment of the present invention.

FIG. 27 is a cross-section of a power conversion device of a sixteenthembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 12, there is a first schematic drawing of a magneticthin film of the present invention. A magnetic thin film 20 is of amagnetic material such as Fe and the like. For example, magnetic fineparticles (magnetic particles 22) coated with an insulating film 23 aredispersed in a medium such as a resin 21. This film is formed by using acoating method in which this medium is coated, dried, and sintered ontop of a semiconductor substrate or on top of an insulated substrate.Therefore, this film is an aggregate of cellular structures in whichmagnetic particles 22 are surrounded by resin 21. Furthermore, themagnetic qualities of magnetic thin film 20 are approximately determinedby the physical constants of magnetic particles 22 which are dispersedin resin 21 or aggregated. Its electrical resistance is approximatelydetermined by the electrical resistance of insulating film 23 and resin21 that surround magnetic particles 22. As a result, the electricalresistance of magnetic thin film 20 is the sum of the resistances ofinsulating film 23 and resin 21 and is a high resistance.

The aforementioned cells containing magnetic particles 22 can easilyalign in one direction or can scatter with a small magnetic field. As aresult, a magnetic thin film 20 with a small coercive force is obtained.Furthermore; for the magnetic flux density, the basic value is providedby the magnetic material. The magnetic flux density can be increased inapproximate proportion with the density of the aforementioned cells.

As described above, by not using a sputter method and using a coatingmethod instead, making a thick film for magnetic thin film 20 can beachieved easily. At the same time, magnetic thin film 20 can be formedwith a flat surface irrespective of the roughness of the undercoat.

Furthermore, magnetic thin film 20 is a metal-non-metal granular film asdescribed above. Magnetic particles 22 are surrounded by insulation, andas a result, compared with the standard magnetic thin films that areformed entirely with magnetic material, they have a large electricalresistance and exhibit excellent soft magnetic qualities in highfrequency regions.

Magnetic thin film 20 will be described further. Magnetic materialpowder of diameter approximately several 10's nm is dispersed in a resinof polyimide and the like. This is rotation coated and baked (sintered).The solvent component is removed, and this becomes a film. Each one ofthe magnetic powder of several 10's nm is surrounded by resin 21. Theseare dispersed or aggregated to form a film.

The above described magnetic material powder does not always have to bedispersed in a resin with high viscosity such as polyimide. The magneticmaterial powder can be coated in a condition in which it is dispersed ina solvent. This solvent can be evaporated, and ultimately, the magneticmaterial powder is an aggregated condition (refer to FIG. 13). Even withthis condition, a satisfactory performance is achieved. Furthermore,when magnetic material powder is coated with an oxide film, for example,even when it contacts a conductor that is placed near it, an electricalshort does not result, and thus, this is more desirable. Referring tothe figure, there is a magnetic thin film 26, a magnetic particle 27,and an oxide film 28. Magnetic particle 27 is a Fe fine particle coveredwith oxide film 28.

By dispersing magnetic powder in a resin or a solvent and coating onto asubstrate, a magnetic powder is formed on top of the substrate.Depending on the form of the substrate, the magnetic powder can be alayer or film exhibiting a uniform distribution, or it can be filledinto grooves in the spaces of a thin film coil, for example.

Next, this magnetic thin film and its manufacturing method and amagnetic component that uses this magnetic thin film and itsmanufacturing method will be described more concretely.

Referring to FIG. 1, there is a cross-section of the principal part ofthe magnetic thin film of the first embodiment of the present invention.A magnetic particle 2 of size 20 nm is formed by surrounding Fe fineparticles with a thin oxide film 3 of a thickness of several nm's. Amagnetic thin film 4 has a structure in which magnetic particles 2 arescattered in a polyimide film 1 at approximately 100 nm intervals.Stated differently, magnetic thin film 4 has a structure whereinentities (the aforementioned cells) in which magnetic particles of 20 nmis surrounded by polyimide of approximately 100 nm thickness are placedapproximately uniformly in polyimide. Furthermore, in terms ofmanufacturing the magnetic component, the practicable range forthickness W of magnetic thin film 4 is from several μm to several 10'sof μm. If the thickness is less than several μm, it is difficult toachieve a magnetic flux density that is necessary for a magneticcomponent. As a magnetic component, adequate magnetic qualities can beachieved if the thickness W of the magnetic thin film is several 10's ofnm.

For a diameter L1 of the aforementioned magnetic particle, around 10 nmto 30 nm is a practicable size. If diameter L1 is less than 10 nm, thedensity of cells becomes small, and the magnetic flux density becomestoo small. Furthermore, if diameter L1 exceeds 30 nm, the cells can notbe scattered uniformly, and it is difficult to achieve a uniformmagnetic quality over the entire thin film.

Furthermore, an interval L2 between magnetic particles of 0 nm toseveral 100 nm is preferred. With an interval L2 of 0 nm, the magneticparticles are in contact with each other. When interval L2 exceedsseveral 100 nm, the density of cells becomes small, and the magneticflux density becomes too small.

Referring to FIG. 2, a second embodiment of the present invention isshown, and it is a manufacture method for the magnetic thin film of thefirst embodiment. The magnetic particle that is used has an averageparticle size of 20 nm and has the surface of Fe covered with an oxidefilm.

The volume ratio of the oxide film portion is approximately around 5% ofthe total volume of the particle. 100 g of these magnetic particles ismixed with 150 g of polyimide and 200 g of toluene. In order to have auniform dispersal, this is mixed with a mixing device. The mixing deviceis described below. A sample container 7 holding the solution ofmagnetic particles, polyimide, and solvent is set at the center of threepairs of electromagnetic coils 8, electromagnetic coils 9, andelectromagnetic coils 10. Electromagnetic coils 8, 9, 10 are placed inthree directions of X, Y, Z axis. Each pair of electromagnetic coils 8,electromagnetic coils 9, and electromagnetic coils 10 is sequentiallyoperated at a period of 3 kHz with a 1 kHz delay for each. As a result,the magnetic particles dispersed in the medium of polyimide and solventperiodically shift sequentially in the X, Y, Z direction along themagnetic field (48 kA/m) created by electromagnetic coils 8, 9, 10. Thisoperation is continued for approximately 3 hours. A dispersion solution6 (medium in which magnetic particles are dispersed) is completed insample container 7. Dispersion solution 6 can be coated to a thicknessof 20 μm on top of a 6 inch phi silicon substrate at a rotationfrequency of 500 rpm, for example. This is baked for 1 hour at 300° C.Thereupon, a magnetic thin film is formed. The magnetic thin film has astructure in which 20 nm magnetic particles surrounded by approximately100 nm thick polyimide are approximately uniformly arranged.Furthermore, if the medium is only toluene, it has a structure (FIG. 13)wherein the 20 nm magnetic particles are in contact via the oxide films.

The manufacturing method for the dispersion solution shown here is onlyone example. The aforementioned X, Y, Z directions can be dividedfurther.

In this manner, magnetic thin film 4 can be easily formed on top of thesubstrate. In other words, magnetic thin film 4 is well suited for massproduction and can be made into a thick film. Because it is a simpleprocess, it can be formed at a low cost. Furthermore, because magneticthin film 4 is a metal-non-metal granular film, it has soft magneticqualities.

Next, an embodiment of a thin film inductor as one example of a magneticcomponent using magnetic thin film 4 is described. In addition, anembodiment for its manufacturing method is also described.

Referring to FIG. 3, a third embodiment of the present invention isshown. Referring to FIG. 3, there is shown a cross-section of a thinfilm inductor that uses the magnetic thin film of the first embodiment.This embodiment is a thin film inductor in which on top of asemiconductor substrate (silicon substrate) on which IC or a powerswitching element is formed, the thin film inductor connects with thepower switching element and the like.

On top of a silicon substrate 31, a 10 μm thick polyimide film 32 isformed. On top of this, a magnetic thin film 33 with a thickness of 20μm is formed. Magnetic thin film 33 is a polyimide film containing Fefine particles as shown in FIG. 1. On top of magnetic thin film 33, apolyimide film 34 with a thickness of 10 μm is formed. On top ofpolyimide film 34, a patterned Ti/Au film 41 and a Ti/Au connectionconductor 39 are formed. On top of this, a Cu coil 35 with a height 35μm, width 90 μm, and space 25 μm, and a polyimide layer 36 that fillsthe space are formed. On top of this, via a 10 μm thick polyimide film37, a magnetic thin film 38 with a thickness of 20 μm is formed.Magnetic thin film 38 is a polyimide film containing Fe fine particlesas shown in FIG. 1. Magnetic thin film 33 and magnetic thin film 38 ofthis structure are magnetic thin films of FIG. 12 or FIG. 13. This thinfilm inductor is a 4 mm square, and Cu coil 35 is a square spiral with aturn number of 16. Referring to Table 2, the thin film inductorqualities when this method of the present invention is used is shown.TABLE 2 Qualities of the thin film inductor of Embodiment 1 (4 mmsquare, 16 turn) Frequency 3 MHz, Operation conditions driving current0.35 A Inductance value L (microH) 0.95 Direct current resistance Rdc(ohm) 0.8 Alternating current resistance Rac (ohm) 3.38

Compared to the qualities of the Co amorphous magnetic film of the priorart (Table 1), the electrical resistance is high, and over-current doesnot flow as easily. With the alternating current resistance, theresistance is reduced by the amount resulting from over-current. As aresult, the alternating current resistance is smaller.

Referring to FIG. 4, this is the fourth embodiment of the presentinvention and shows a manufacturing method for a thin film inductor ofthe third embodiment. Referring to FIG. 4(a) to FIG. 4(c),cross-sections of the manufacturing process in the process sequence isshown.

Polyimide film 32 with a thickness 10 μm is formed on top of siliconsubstrate 31. On top of this, magnetic layer 33 with a thickness 20 μmis formed. Afterwards, an opening 40 that reaches silicon substrate 31is formed (FIG. 4(a)). Next, on top of this, polyimide film 34 ofthickness of 10 μm is formed, and an opening that is continuous withopening 40 is formed. Afterwards, an undercoat metal (Ti/Au film 41) forforming Cu coil 35 by plating and a connection conductor 39 forconnecting silicon substrate 31 with Cu coil 35 are sputter deposited.Patterning is conducted, and polyimide 36 that acts as a plating mask isformed (FIG. 4(b)). Afterwards, with polyimide 36 as a mask, Cu coil 35with a height of 35 μm, width 90 μm, space 25 μm is formed. Polyimidelayer 36 is a mask that fills the spaces in Cu coil 35. On top of Cucoil 35 and polyimide layer 36, polyimide film 37 with a thickness of 10μm is formed. On top of this, magnetic layer 38 with a thickness of 20μm is formed, and the thin film inductor is completed (FIG. 4(c)).

Referring to FIG. 5, a cross-section of the principal parts of a thinfilm inductor of a fifth embodiment of the present invention is shown.The difference between this embodiment and the third embodiment is thata plating mask 65 is a photosensitive polyimide film in which magneticparticles are dispersed as in FIG. 12. Ultimately, the structure is onewhere a Cu coil 66 is surrounded by this magnetic medium (aphotosensitive polyimide film in which magnetic particles are dispersed)(in the third embodiment, the magnetic medium is only placed above andbelow Cu coil 35. There is leakage of magnetic flux generated on theside surfaces). There is very little leakage flux, and a thin filminductor having qualities of a higher inductance value and a loweralternating current loss can be achieved.

A polyimide film 62 is formed on top of a silicon substrate 61 in whicha semiconductor element is built in. On top of polyimide film 62, amagnetic thin film 63 with a thickness of 20 μm is formed. In magneticthin film 63, Fe particles having a particle size of 20 nm and havingits surface covered by oxide are dispersed in a non-photosensitivepolyimide. On top of magnetic thin film 63, a plating electrode of aTi/Au film 64 and a Ti/Au connection conductor 69 are formed. Instead ofthe usual photosensitive polyimide film, a magnetic thin film in whichmagnetic particles are dispersed is patterned. Using this as a platingmask 65, Cu coil 66 with a thickness of 30 μm and a turn number of 16 isformed by plating. On top of this, a magnetic thin film 68 with athickness of 20 μm is formed. In magnetic thin film 68, Fe particleshaving a particle size of 20 nm and having its surface covered by anoxide are dispersed in a non-photosensitive polyimide. With the thinfilm inductor obtained in this manner, the exterior of Cu coil 66 isentirely covered with a resin in which magnetic particles are dispersed(magnetic thin film). As a result, the magnetic flux that is created bythe current flowing through Cu coil 66 is tightly bound. Therefore,compared to the prior art and compared to the first embodiment, becausethe inductance value is large and the leakage flux is small, thealternating current resistance is small. This is shown in the results inTable 3. TABLE 3 Qualities of the thin film inductor of Embodiment 2 (4mm square, 16 turn) Frequency 3 MHz, Operation conditions drivingcurrent 0.35 A Inductance value L (microH) 1.15 Direct currentresistance Rdc (ohm) 0.8 Alternating current resistance Rac (ohm) 2.38

Referring to FIG. 6, this is the sixth embodiment of the presentinvention and shows the manufacture method for the thin film inductor ofthe fifth embodiment. Referring to FIGS. 6(a)-6(c), there are shown thecross-section diagrams of the manufacture process in the processsequence.

Polyimide film 62 is formed on top of silicon substrate 61 with abuilt-in semiconductor element. In the same manner as in the fourthembodiment, Fe particles that have their surfaces covered with an oxideand that have a particle size of 20 nm are dispersed in anon-photosensitive polyimide. This is rotation coated at a rotationfrequency of 500 rpm and baked. Magnetic thin film 63 of thickness 20 μmis formed on top of polyimide film 62. On top of magnetic thin film 63,in the same manner as in the prior art, a plating electrode of Ti/Aufilm 64 and Ti/Au connection conductor 69 are formed (FIG. 6(a)). Next,photosensitive polyimide in which magnetic particles are dispersed isrotation coated at a rotation frequency of 200 rpm and baked. This isexposed to light and developed, and plating mask 65 with a thickness of30 μm is formed. As with the prior art, Cu coil 66 with a thickness of30 μm and a turn number of 16 is formed (FIG. 6(b)). Again, on top ofthis, non-photosensitive polyimide in which Fe particles having theirsurfaces covered with an oxide and having a particle size of 20 nm aredispersed is rotation coated at a rotation frequency of 500 rpm andbaked. Magnetic thin film 68 of thickness 20 μm is formed, and the thinfilm inductor is completed (FIG. 6(c)).

Referring to FIG. 7, a cross-section diagram of the principal parts of athin film inductor of the seventh embodiment of the present invention isshown.

A polyimide film 72 is formed on top of a silicon substrate 71 in whicha semiconductor element is built in. On top of polyimide film 72, amagnetic thin film 73 with a thickness of 10 μm is formed. With magneticthin film 73, Fe fine particles that are covered with an oxide film andthat have an average particle size of 20 nm are aggregated as in FIG.13. On top of magnetic thin film 73, a plating electrode of a Ti/Au film74 and a connection conductor 79 which connects with silicon substrate71 are formed. On top of this, a Cu coil 76 of thickness 30 μm and 16turns is formed. A magnetic thin film 78 in which Fe fine particles areaggregated is formed between and above Cu coil 76, and the thin filminductor is completed. Compared with the third and fifth embodiments,the magnetic bonding is strong because there is no resin (however,because fine particles that have their surfaces covered with an oxideare aggregated, they are electrically insulated). As a result, referringto Table 4, compared to the thin film inductors of the third and fifthembodiments, a thin film inductor with a high inductance value and asmall alternating current resistance is obtained. TABLE 4 Qualities ofthe thin film inductor of the third embodiment (4 mm square, 16 turn)Frequency 3 MHz, Operation conditions driving current 0.35 A Inductancevalue L (microH) 2.15 Direct current resistance Rdc (ohm) 0.8Alternating current resistance Rac (ohm) 1.38

Referring to FIG. 8, this is the eighth embodiment of the presentinvention and shows the manufacture method for the thin film inductor ofthe seventh embodiment. Referring to FIGS. 8(a)-8(c), there are shownthe cross-section diagrams of the manufacture process in the processsequence.

A toluene solvent containing Fe fine particles that are covered with anoxide film and have an average particle size of 20 nm is coated with abrush onto silicon substrate 71 which has a built-in semiconductorelement. After eliminating the solvent by drying at 100° C. (3 minutes),magnetic thin film 73 with a thickness of 10 μm is formed by baking at250° C. (15 minutes) (FIG. 8(a)). In magnetic thin film 73, magneticparticles are aggregated as in FIG. 13. On top of magnetic film 73,plating electrode of Ti/Au film 74 and plating mask 75 are formed. Cuplating is conducted to form Cu coil 76 with a thickness of 30 μm and 16turns (FIG. 8(b)). Afterwards, the plating mask is bleached in an oxygenplasma and incinerated and removed (or it can be removed by a solvent).Next, in the same manner as the method at the start, toluene solventcontaining Fe fine particles is coated with a brush, dried, and baked.This results in the formation of magnetic thin film 78 between the Cucoil and on top of the Cu coil (FIG. 8(c)). With magnetic thin film 78,the Fe fine particles are aggregated.

With power source components such as small and thin reactors andtransformers comprising a conductor coil and a magnetic thin film, themagnetic thin film part of these power source components can bemanufactured by a simple process by using the methods described above.This simple process includes coating with a resin or solvent in whichmagnetic fine particles are dispersed and drying and baking this.Furthermore, because the magnetic thin film that is formed can have ahigh electrical resistance, the reduction in manufacturing costs and thereduction in loss can be achieved simultaneously for the magneticcomponents such as reactors and transformers.

Referring to FIG. 9, a cross-sectional diagram of the principal parts ofa thin film inductor of the ninth embodiment of the present invention isshown. The difference between this embodiment and the sixth embodimentis that the thin film inductor is formed not on top of a semiconductorsubstrate but on top of an insulating substrate 31 a.

Referring to FIG. 10, a cross-sectional diagram of the principal partsof a thin film inductor of the tenth embodiment of the present inventionis shown. The difference with the seventh embodiment is that the thinfilm inductor is formed not on top of a semiconductor substrate but ontop of an insulating substrate 61 a.

Referring to FIG. 11, a cross-sectional diagram of the principal partsof a thin film inductor of the eleventh embodiment of the presentinvention is shown. The difference with the eighth embodiment is thatthe thin film inductor is formed not on top of a semiconductor substratebut on top of an insulating substrate 71 a.

The qualities of the thin film inductors of these embodiments are thesame as with the embodiments described previously.

Referring to FIG. 18, there is shown a cross-sectional diagram of oneexample of a thin film transformer of the twelfth embodiment of thepresent invention. A primary Cu conductor coil 185 and a secondary Cuconductor coil 185 have a height of 31 μm, width of 90 μm, and space of25 μm. Primary Cu conductor coil 185 and secondary Cu conductor coil 185are formed on top of silicon substrate 184 and are embedded in apolyimide resin in which magnetic particles are mixed in. This thin filmtransformer is a 4 mm square, and the Cu conductor coil has a turnnumber of 16 and is a square spiral. The formation method for thepolyimide resin, which is used in the above construction and which hasmagnetic particles mixed in, will be described more concretely below.For the magnetic particles, particles that have surfaces of Fe coveredwith an oxide film and that have an average particle size of 20 nm areused. The volume ratio of the oxide film portion is 5% or less of thetotal volume of the particle. The manufacturing method for thesemagnetic particles is the same as with the second embodiment describedabove.

Referring to FIG. 19, this is the thirteenth embodiment of the presentinvention and shows a flow diagram of the manufacturing process of thethin film transformer of FIG. 18. Ultimately, this embodiment has astructure in which the coil conductors are surrounded by the magneticmedium. The leakage magnetic flux is low, and the magnetic bonding ofthe primary and secondary coils is tight, and a thin film transformerwith low loss is achieved. Referring to FIG. 19, the process flow willbe described. Fe particles that have their surfaces covered with anoxide and that have a particle size of 20 nm are dispersed in anon-photosensitive polyimide. This is rotation coated at a rotationfrequency of 500 rpm and baked on top of a silicon substrate 191 with abuilt-in semiconductor element. A thin film of a magnetic resin 192 witha thickness of 5 μm is formed. On top of this, in the same manner as inthe prior art, a plating electrode 193 of Ti/Au is formed (FIG. 19(a)).Next, magnetic particle dispersion medium that is changed tophotosensitive polyimide is rotation coated at a rotation frequency of200 rpm and baked. This is exposed to light and developed, and a Cuplating coil 195 with a thickness of 30 μm and a turn number of 16 isformed (FIG. 19(b)). A magnetic resin 194 is in the spaces in Cu platingcoil 195. Again, on top of this, non-photosensitive polyimide, in whichFe particles having their surfaces covered with an oxide and having aparticle size of 20 nm are dispersed, is rotation coated at a rotationfrequency of 500 rpm and baked. A magnetic thin film 196 with thicknessof 5 μm is formed (FIG. 19(c)). By repeating the above process, asecondary coil that is surrounded by magnetic dispersion medium issimilarly formed, and the thin film transformer is completed (FIG.19(d)). With the transformer obtained in this manner, the exterior ofthe Cu coil conductors are entirely covered with resin in which magneticparticles are dispersed. As a result, the magnetic flux created by thecurrent flowing in the primary coil conductor and the secondary coilconductor are tightly bound. Therefore, because the leakage magneticflux is smaller compared to the prior art, the resistance loss is alsosmall.

Referring to FIG. 20, there is shown a cross-sectional diagram of a leadwire of the fourteenth embodiment of the present invention. With acopper wire of a diameter 0.5 mm, resin that has a thickness of 100 μmand that has dispersed magnetic particles is filled in a device shown inFIG. 21. The lead wire is formed by passing the copper wire through thedevice at a constant speed. The manufacture method for the magneticparticles is the same as in the second embodiment described above.

Referring to FIG. 22(a), there is shown a sketch diagram of a coil inwhich the lead wire created in the fourteenth embodiment is wound into aspring-shape. Referring to FIG. 22(b), a partial cross-section alongsurface A-A′ is shown.

Referring to FIG. 22, the filled and unfilled circles are Cu lead wires.An outer circle 221 that surrounds the Cu lead wire shows the portionwhich is coated with resin. This is a ten turn coil, and it iscylindrical with outer dimensions of a diameter of approximately 1 mmand height of 7 mm. Referring to FIG. 23, there is shown the generatedmagnetic fields created by the current flowing through the coil in thecross-sectional drawing (FIG. 22 b). Referring to FIG. 23, the filledcircles show the current flowing into the page, and the unfilled circlesshow the current flowing out of the page. The magnetic field created bythe current flowing through the coil is surrounded by the resin whichcontains the magnetic particles. The coils are embedded in magneticfields that are in the direction of the arrows shown in the figure.Because the magnetic flux created by the current flowing through thecoil is enclosed in the resin, any mutual electromagnetic interferencewith an outside element is avoided. In addition, it also has thecapability of a small inductor of 10 turns.

On the other hand, referring to FIG. 24, if these elements are placed inclose contact and two are laid out side by side, it becomes atransformer with a resin, voltage ratio of 1:1. The voltage ration canbe changed by placing coils with different turn numbers in closecontact. The magnetic field generated in the primary coil is transferredto the secondary coil via the resin containing magnetic particles. Thisis the same as the standard transformer in which there is a coil arounda magnetic core. The advantage of this invention is that the magneticcore, which is heavy and bulky, is eliminated, and its function is stillexhibited. Referring to the figure, the arrows show the direction of thelines of magnetic force. Referring to FIG. 25, there is shown an examplewhere the principles of FIG. 24 is applied to a current detectionsensor. The coated lead wire of the present invention is used as themain circuit lead wire. A section (part A) of this main circuit leadwire is coiled as in FIG. 22. Next to section A, there is a coiled wireB (using the lead wire of the present invention) that is a sensor partand is separate from the main circuit. Section A and sensor part B areprovided in a unitary manner. As a result, a voltage that isproportional with the size of the current flowing through the maincircuit is generated at both ends of sensor part B. By calibrating inadvance, the size of the current flowing through the main circuit can beestimated by the voltage generated at both ends of sensor part B. Thiscan be used as a current detection sensor. As described previously,sensor part B can be made very small. As a result, because it cansatisfy the demands of being small and light, it can be attached to anysection.

As described above, the lead wire of the present invention not onlyavoids the problem of mutual interference, but at the same time it canalso be equipped with a positive and functional role. Stated moreconcretely, by coating a lead wire with a magnetic material that iselectrically insulated, the lead wire also has the functionality of amagnetic component. The advantages of the lead wire of the presentinvention can be exemplified as follows.

-   1) Because the electrical resistance is determined by the resin that    surrounds the magnetic fine particles, the resistance of the film    itself can be a high resistance to the same degree as the resin. An    adequate electrical insulation can be ensured. At the same time,    because the electric current magnetic field can be enclosed in this    coating, any electromagnetic interference with an adjacent lead wire    can be prevented.-   2) Because the same method as used in the formation of the enamel    wires of the prior art can be used, new equipment for implementing    the present invention is unnecessary, and manufacture can be    conducted cheaply.-   3) If the lead wire is a thin wire similar to enamel wire, any shape    can be created by coiling or bending and the like. As a result,    without having to make a magnetic component by coiling a lead wire    around a magnetic core as in the prior art, a magnetic component can    be made with just the lead wire. Furthermore, its magnetic qualities    are approximately determined by the magnetic particles that are    dispersed in resin or are aggregated. As a result, the manufacture    of the desired magnetic component can be conducted easily.

Instead of polyimide as the resin, enamel resin, vinyl chloride resin,epoxy resin, and the like can also be used.

Referring to FIG. 26, there is shown a cross-section of a powerconversion device of the fifteenth embodiment of the present invention.Referring to FIG. 26, there is a semiconductor integrated circuitsubstrate 261, a metal thin wire 262, a polyimide insulation film 263, acoil conductor (Cu) 264, a lower magnetic film 266, a chip condenser267, a printed board 268, a soldering ball 269, and a sealing resin 271containing magnetic particles. The magnetic particles are prepared inthe same manner as in Embodiment 2 described previously.

Stated more concretely, coil conductor 264 (a planar coil) is formed bythe standard method on top of semiconductor integrated circuit substrate261 via polyimide insulation film 263 and is formed up to the top partof polyimide insulating film 263. Next, this is cut out as a chip bydicing. While this is mounted on top of the printed board and withoutusing silica which is normally used as a skeleton material, this issealed by a mold resin with a one-sided transfer mold used in BGA andthe like. This mold resin contains 75-85% of magnetic powder ofEmbodiment 2 described previously, or magnetic powder or ferrite powderof particle size of approximately 0.1-120 μm. Sealing resin 271containing magnetic particles is formed in this manner. Afterwards,other individual components are mounted on top of the printed board, andthe entirety is sealed with sealing resin 270 of the prior art.

The magnetic particles of the prior art have a thermal expansioncoefficient of approximately 3 times that of silica. As a result, thestress applied to the silicon substrate is increased, and there is anegative impact on reliability and quality. There is the possibility ofgenerating equipment that does not satisfy specifications. However, if amold resin containing the magnetic thin film of the present invention at25-30% dispersion is used, the stress applied to the silicon substratecan be reduced.

Referring to FIG. 27, there is shown a cross-sectional diagram of apower conversion device of the sixteenth embodiment of the presentinvention. Referring to FIG. 26, the numerals are the same as in FIG.26, and therefore, the descriptions are omitted. In the sixteenthembodiment, in the same manner as the fifteenth embodiment, a planarcoil is formed to the top part of polyimide insulation film 263. Aftercutting out the chip by dicing, this is affixed and connected to a leadframe 272, and this is connected to the inner leads by metal thin wires262. Afterwards, without using silica which is normally used as askeleton material, this is sealed by a transfer mold using a mold resin.This mold resin contains 75-85% of metal magnetic powder-or ferritepowder of approximate particle size of 0.1-120 μm. This is made into amold package of DIP, QFP, QFN, and the like.

According to the fifteenth and sixteenth embodiments, the accumulationand etching process of the upper magnetic thin film becomes unnecessary.Complexity in the manufacture process can be avoided. Furthermore,stress due to the shrinking of the magnetic thin film arising from heattreatment can also be prevented. In addition, the magnetic particles canalso act as the skeleton material for the sealing resin. Furthermore,because an upper magnetic thin film is not formed, the warping of thesubstrate due to its shrinkage can be reduced. The generated stress witha construction of the prior art is 5.8×10⁶ (dyn/cm). With a siliconsubstrate of phi 6 inches (thickness 625 μm), this results in a warpingof approximately 1200 μm. With the fifteenth embodiment, the warping ofthe silicon substrate can be reduced to ⅔ of the prior art. Furthermore,because the inductor side surfaces are covered with a magnetic thinfilm, the leakage magnetic flux can be reduced.

Furthermore, with the present invention, for the resin in which theaforementioned magnetic particles are dispersed, it is preferred toselect an organic magnetic polymer that is magnetic in order to have alarge magnetic interaction between the magnetic particles and ultimatelyto increase the magnetic quality of the entire film. By doing so, evenif the density of magnetic particles in the resin is low compared topolymers that are not magnetic, the magnetic interactions betweenmagnetic particles are strengthened via the polymer. A magnetic particledispersion resin having the desired magnetic quality is achieved.

When the material powder for the magnetic particles is a magnetic oxide,even if there is contact with an adjacent conductor, an electrical shortdoes not result, and this is preferred.

Stated more concretely, in the present invention, examples of thepreferred organic magnetic polymer include cross conjugated polycarbeneor a conjugated polymer having a main chain of polyacetylene andpolydiacetylene.

A cross conjugated polycarbene can be obtained in the following manner.

A precursor diazo compound shown in the following general formula issynthesized.

Next, UV light is shone on this precursor. By conducting a photolysisreaction, the following cross conjugated polycarbene can be obtained.

In the formula, the dot represents a radical electron having a spin ofan open-shell structure. This is a result of the dissociation of the N₂in chemical formula 1 by a photochemical reaction. This is the source ofthe magnetism of this resin. Furthermore, m can be selected as desiredfrom 10 through on the order of 10². For example, it can be selected tobe 30 or less.

Using this cross conjugated polycarbene, a magnetic thin film as shownin the previously described second embodiment is created. This resultedin a structure in which magnetic particles of 20 nm are surrounded by anapproximately 100 nm thick polycarbene, and these are arrangedapproximately uniformly. Furthermore, in the above, a cross conjugatedpolycarbene is used, but a poly (p-oxyphenyl acetylene) shown below canalso be used. A polydiacetylene compound can also be used.

For the polymerization of the substituted acetylene, a catalyst such asan olefin metathesis catalyst (for example WCl₆-SnPh₄) and Rh (I)catalyst of Furlani et al can be used.

The method of usage for the aforementioned magnetic organic polymer isnot particularly limited. For example, a magnetic component can be madeby the standard methods.

Referring to Table 5, there are shown the qualities of the thin filminductor with a magnetic film of the prior art, the thin film inductorwith a magnetic film of the present invention in which Fe fine particlesare dispersed in polyimide resin, the thin film inductor with a magneticfilm of the present invention in which Fe fine particles are dispersedin cross conjugated polycarbene resin, the thin film inductor with amagnetic film of the present invention in which Fe fine particles aredispersed in poly (p-oxyphenyl acetylene) resin which is describedbelow. As is clear from comparing these tables, compared to the priorart, thin film inductors with magnetic films in which Fe fine particlesare dispersed have excellent quality in terms of inductance and loss.However, compared to when the resin is non-magnetic such as polyimide,the inductance is higher when a magnetic resin such as polycarbene andthe like is used. This can be understood to be the result of astrengthened magnetic bonding (interaction) between Fe fine particles.TABLE 5 Qualities of the thin film inductor of the prior art (4 mmsquare, 16 turn) Frequency 3 MHz, Operation conditions driving current0.35 A Inductance value L (microH) 0.95 Direct current resistance Rdc(ohm) 0.8 Alternating current resistance Rac (ohm) 5.38

Qualities of the thin film inductor when the resin is polyimide(4 mmsquare, 16 turn) Frequency 3 MHz, Operation conditions driving current0.35 A Inductance value L (microH) 1.15 Direct current resistance Rdc(ohm) 0.8 Alternating current resistance Rac (ohm) 2.35

Qualities of the thin film inductor when the resin is polycarbene(4 mmsquare, 16 turn) Frequency 3 MHz, Operation conditions driving current0.35 A Inductance value L (microH) 2.12 Direct current resistance Rdc(ohm) 0.8 Alternating current resistance Rac (ohm) 2.35

Qualities of the thin film inductor when the resin is poly (p-oxyphenylacetylene) (4 mm square, 16 turn) Frequency 3 MHz, Operation conditionsdriving current 0.35 A Inductance value L (microH) 1.62 Direct currentresistance Rdc (ohm) 0.8 Alternating current resistance Rac (ohm) 2.35

The present invention provides a magnetic thin film that is well suitedfor mass production, can be manufactured easily, can be made into athick film, and has soft magnetic qualities. The present- invention alsoprovides a magnetic component that uses this thin film, andmanufacturing methods for these, and a power conversion device.

Having described preferred embodiments of the invention with referenceto the accompanying drawings, it is to be understood that the inventionis not limited to those precise embodiments, and that various changesand modifications may be effected therein by one skilled in the artwithout departing from the scope or spirit of the invention as definedin the appended claims.

1. A magnetic thin film, comprising: a resin having magnetic fineparticles dispersed therein.
 2. A magnetic thin film as described inclaim 1, wherein: said magnetic fine particles contain at least onemetal element selected from a group consisting of Fe, Ni, Co, Mn, andCr.
 3. A magnetic thin film as described in claim 1, wherein: said resinis a non-photosensitive resin or a photosensitive resin.
 4. A magneticthin film as described in claim 1, wherein: said resin is an organicmagnetic polymer.
 5. A magnetic thin film as described in claim 4,wherein: said organic magnetic polymer is a cross conjugated polycarbeneor a conjugated polymer that has a main chain of polyacetylene andpolydiacetylene.
 6. A magnetic thin film, wherein: said thin film isconstructed from magnetic fine particles, and said fine particles areaggregated so that said fine particles are in contact with each other.7. A magnetic thin film as described in claim 1, wherein: said fineparticle comprises a magnetic particle and an insulating film thatsurrounds the perimeter of said magnetic particle. 8-11. (canceled) 12.A magnetic component, comprising: a first magnetic thin film and asecond magnetic thin film being magnetic thin films described in claim1; said first magnetic thin film being formed on top of a semiconductorsubstrate via an insulating film; a thin film conductor being formed ina spiral shape on top of said first magnetic thin film; a second resinthat fills spaces in said spiral thin film conductor; said secondmagnetic thin film being formed on top of said thin film conductor andsaid second resin.
 13. A magnetic component as described in claim 12,wherein: said second resin is a magnetic thin film as described inclaim
 1. 14. A magnetic component, comprising: a third magnetic thinfilm and a fourth magnetic thin film being magnetic thin films describedin claim 6; said third magnetic thin film being formed on top of asemiconductor substrate via an insulating film; a thin film conductorbeing formed in a spiral shape on top of said third magnetic thin film;said third magnetic thin film being formed in spaces in said spiral thinfilm conductor; said fourth magnetic thin film being formed on top ofsaid thin film conductor and said third magnetic thin film. 15-17.(canceled)
 18. A magnetic component, comprising: a first magnetic thinfilm and a second magnetic thin film being magnetic thin films describedin claim 1; said first magnetic thin film being formed on top of aninsulating substrate via an insulating film; a thin film conductor beingformed in a spiral shape on top of said first magnetic thin film; asecond resin filling spaces in said spiral-shaped thin film conductor;said second magnetic thin film being formed on top of said thin filmconductor and said second resin.
 19. A magnetic component as describedin claim 18, wherein: said second resin is a magnetic thin film asdescribed in claim
 1. 20. A magnetic component, comprising: a thirdmagnetic thin film and a fourth magnetic thin film being magnetic thinfilms described in claim 6; said third magnetic thin film being formedon top of an insulating substrate via an insulating film; a thin filmconductor being formed in a spiral shape on top of said third magneticthin film; said third magnetic thin film being formed in spaces in saidspiral-shaped thin film conductor; said fourth magnetic thin film beingformed on top of said thin film conductor and said third magnetic thinfilm.
 21. A magnetic component as described in claim 12, wherein: saidmagnetic component is a transformer.
 22. A magnetic component asdescribed in claim 12, wherein: said magnetic component is a powerconversion device.
 23. A lead wire, wherein: said lead wire is coveredwith a magnetic thin film described in claim
 1. 24. A magneticcomponent, comprising: a lead wire as described in claim 23 being usedas a coil.
 25. A current sensor, comprising: a magnetic sensor beingprovided on a lead wire described in claim
 23. 26. A magnetic componentas described in claim 12, comprising: an insulating film being betweensaid first magnetic thin film and said thin film conductor and saidsecond resin and between said thin film conductor and said second resinand said second magnetic thin film.
 27. A magnetic component asdescribed in claim 12, wherein: said thin film conductor and said secondresin is formed as two layers via an insulating film.
 28. A powerconversion device, comprising: a magnetic component, comprising: amagnetic thin film as described in claim 1 being formed on top of asemiconductor integrated circuit substrate via an insulating film; athin film conductor being formed in a spiral shape on top of saidmagnetic thin film; a second resin being filled in spaces in saidspiral-shaped thin film conductor; said magnetic component being mountedon top of a wiring substrate; said magnetic component being resin sealedby a resin in which magnetic fine particles are dispersed.
 29. A powerconversion device, comprising: a magnetic component, comprising: amagnetic thin film as described in claim 1 being formed on top of asemiconductor integrated circuit substrate via an insulating film; athin film conductor being formed in a spiral shape on top of saidmagnetic film; a second resin being filled in spaces in saidspiral-shaped thin film conductor; said magnetic component being mountedonto a lead frame; a lead terminal being connected to said magneticcomponent by a metal thin wire; said lead terminal and said lead frameand said magnetic component are resin sealed by a resin in whichmagnetic fine particles are dispersed.
 30. A power conversion device asdescribed in claim 28, wherein: said thin film conductor and said secondresin are formed in two layers via an insulating film.
 31. A powerconversion device as described in claim 28, wherein: an insulating filmis formed on top of said thin film conductor and said second resin.